The purification of gases by means of physically acting scrubbing solutions and particularly the removal of H.sub.2 S and CO.sub.2 from gases by such scrubbing processes has been known for a long time.
Processes of this kind have been described in German Pat. No. 1,494,806 and in U.S. Pat. Nos. 3,531,917 and 3,710,546.
It is also known to regenerate the laden absorbent solution by a pressure relief, heating or stripping treatment or by a combination of such treatments. Suitable physically acting scrubbing solutions include methanol and N-methylpyrrolidone (NMP). The gas scrubbers are usually operated at temperatures in the range from +60.degree. to -80.degree. C.
During the scrubbing of the gas the scrubbing solution absorbs not only impurities but also certain quantities of the valuable gases which constitute the main constituents of the gas to be scrubbed.